For a conventional solar cell module based on copper indium selenide (CIS), it is basically formed as a solar cell that is made by depositing a metallic back layer, a p-type absorber layer, a high-resistance buffer layer and a n-type window layer on a substrate. Moreover, after being sandwiched inside a weather-resistance film made of a filling material, such as ethylene vinyl acetate (EVA), the so-constructed solar cell is further being covered by a compactly fitted inside a glass housing while being framed by a frame structure that can be made of aluminum. Thereby, the solar cell module that is being framed inside the frame structure is capable of preventing the incursion of water and moisture into the glass housing and thus improving the weather resistance of the solar cell module.
Generally, while viewing a conventional CIS-based solar cell module, which is formed as a solar cell element sandwiched between a glass cover and a glass substrate and framed inside an aluminum frame structure while having an electrode assembly protruding outside the frame structure, only the aluminum frame structure, the electrode assembly and the solar cell element is clearly visible. In addition, in some cases, the aluminum frame structure is coated in a color the same as that of the solar cell element, usually in black. However, since the electrodes in many conventional solar cell modules are silver in color, as the metal lines 71 formed on the solar cell element that is shown in FIG. 2, the appearance of the resulting solar cell module may not be very presentable by the different coloration of electrode assembly and the solar cell element.
In many conventional solar cell modules as the one disclosed in Japanese patent laid-open Publication No. 2001-298202, there are a plurality of bumps formed on the surface of a colorless transparent float glass, such as a Borofloat glass, by means of screen printing using a ceramic ink, whereas the plural bumps are to be used for enhancing the diffuse reflection of the light projected on the glass, resulting that the light income of the solar cell module can be increased. However, although there are the plural bumps formed on the surface of a colorless transparent float glass, still the electrode assembly is left exposed and thus the appearance of the solar cell module is not improved.
Generally, the ceramic ink that is black in color is made of zirconium oxide or aluminum oxide that is doped with about 5%˜20% in weight of any one or two dying materials selected from the group consisting of: manganese dioxide, ferroso-ferric oxide, cobaltous oxide, nickelous oxide, and chrome oxide, by means of calcination, as disclosed in Japanese patent laid-open Publication No. 7-56070.
From the above description, it is noted that in conventional CIS-based solar cell modules, the silver-colored electrode assembly, as the metal lines 71 shown in FIG. 2, is always exposed without any effort trying to unify the coloration of the whole CIS-based solar cell module in view of beautification.
For hiding the silver-colored electrode assembly or for enabling the same to be not as obvious as it is now, it is possible to add an additional step in the solar cell module manufacturing process for coating a layer of clack ink on the silver-colored electrode, or attaching a black vinyi tape on the silver-colored electrode assembly. However, the addition of such the aforesaid step in the solar cell module manufacturing process not only will cause the manufacturing process to become much more complex, but also will cause the manufacturing cost to increase accordingly.
Moreover, there is a solar cell module disclosed in TW pat. Pub. No. 200816506, in which the silver-colored electrode assembly is hidden under a coating of a black ceramic layer for unifying the coloration of the whole solar cell module and thus improving the appearance of the same, without causing the manufacturing process of the solar cell module to become too complex. That is, using the technique disclosed in the aforesaid patent publication, the solar cell element and the electrode assembly formed thereon are enabled to appear in the same color. In detail, there is a rim of clack ceramic layer formed around the periphery of the cover glass at position corresponding to the silver-colored electrode assembly on the solar cell element, by that the coloration of the whole solar cell module is unified and thus the beautification of the same is improved. It is noted that although the formation of the black ceramic layer can be achieved at the same time during the thermal strengthening treatment of the cover glass, the manufacturing cost is still increased due to not only the comparatively longer heating time required for achieving the formation of the black ceramic layer, but also due to the material cost of the black ceramic layer as well as the additional step required for processing the same.